Nematicides from Juglandaceae and methods of use thereof

ABSTRACT

The invention provides compositions and methods for inhibiting nematode damage to plants. The compositions comprise acid extracts or alcohol extracts from juglone-producing members of the Juglandaceae. The methods comprise applying the compositions of the invention to soil contacting roots of nematode-susceptible plants.

CROSS-REFERENCES TO RELATED APPLICATIONS

This application is a divisional application of U.S. application Ser.No. 11/792,029, filed Jul. 18, 2007, now U.S. Pat. No. 7,927,635, whichis a national stage entry of PCT/US05/43484, filed Nov. 30, 2005, whichclaims priority to U.S. Provisional Application No. 60/632,082, filedNov. 30, 2004, the contents of which are hereby incorporated byreference.

STATEMENT AS TO RIGHTS TO INVENTIONS MADE UNDER FEDERALLY SPONSOREDRESEARCH AND DEVELOPMENT

Not Applicable

REFERENCE TO A “SEQUENCE LISTING,” A TABLE, OR A COMPUTER PROGRAMLISTING APPENDIX SUBMITTED ON A COMPACT DISK

Not Applicable

BACKGROUND OF THE INVENTION

Nematodes (sometimes known as “roundworms”) are the most commonmulti-cellular animals on earth. There are thousands of species. Whilemost species are not harmful to plants, unfortunately, some are plantparasites. Some, such as pin nematodes (Paratylenchus) and stubby-rootnematodes (Trichodorus and Paratrichodorus), live outside the plant(that is, they are ectoparasites) pierce root cells with a body partknown as the stylet and suck out the content of root cells. Others, suchas root-lesion nematodes (Pratylenchus) enter the plant root and movethrough it, weakening the root system. Root-knot nematodes (Meloidogyne)enter the roots as juveniles and release chemicals which cause theformation of visible galls or “root knots”.

As a group, nematodes cause millions of dollars of damage to turfgrasses, corn and other vegetable crops, cotton plants, and fruit trees.Methods of control include rotating crops and application of chemicals.Biological means such as nematophagous fungi (see, e.g., U.S. Pat. No.6,749,848) have been tried, as have methods such as introducingnucleotide sequences that confer resistance (see, e.g., U.S. Pat. No.6,284,948). Chemicals such as organophosphates have been the majorcommercially used technique for controlling nematodes. Unfortunately,they are toxic to wildlife, and their use is being restricted orterminated due to environmental concerns. Nemacur®, the only nematicideapproved in various states for use on plants after they have beenplanted (“post plant”), is highly toxic to fish and wildlife. Byagreement with the U.S. Environmental Protection Agency, themanufacturer will not be able to sell it after May 2007.

According to Duke, S. O. “Natural pesticides from plants”, pp. 511-517,in J. Janick and J. E. Simon (eds.), ADVANCES IN NEW CROPS, (TimberPress, Portland, Oreg., 1990), many plant species, such as marigolds,chrysanthemums, castor bean, margosa, and some members of the familyAsteraceae are resistant to nematodes. The reference indicates that theactive principle for the nematicidal activity has not been discovered inall of these examples and that no plant-derived products were being soldcommercially for control of nematodes.

Juglone is a naphtaquinone produced by members of the Juglandaceae, andparticularly plants of the genus Juglans. It is exuded particularly bythe black walnut; juglone is toxic to a number of commercially valuableplant types, which therefore cannot be grown in proximity to walnuttrees. Juglone is only slightly soluble in water and does not travelvery far through the soil. Its toxicity to other plants occurs when theroots of the juglone-producing tree come in close proximity to the rootsof a susceptible plant.

In 2001, Wuyts et al. presented a poster stating that juglone had sometoxicity to the endoparasitic nematode Pratylenchus penetrans.Unfortunately, the inability of juglone to travel far through the soiland its toxicity to many commercially valuable plants makes its use as anematicide in the field problematic. In 2002, a California state sciencefair project summary reported that a walnut extract made from steepingcut up branches of walnut in water had some toxicity to root lesionnematodes placed in the extract. In 2003, however, a further Californiastate science fair project summary reported on tests of the ability ofmethyl bromide, methyl iodide, walnut “tea” extract, and commercialcompost to disinfest plant roots of root-knot nematodes. This projectsummary reported that the walnut tea extract failed to disinfest thesoil of the nematodes.

It would be desirable to have alternative means to inhibit nematodeinfestations of plants.

BRIEF SUMMARY OF THE INVENTION

The present invention provides compositions that inhibit nematode growthand methods for doing so. In a first group of embodiments, the inventionprovides composition comprising an acid extract or an alcohol extract ofmaterial from a first juglone-producing plant of the familyJuglandaceae. In some embodiments, the first juglone-producing plant isa member of a genus selected from the group consisting of Carya,Engelhardtia, Juglans, Platycarya and Pterocarya. In some embodiments,the plant is a member of the genus Juglans. In some embodiments, theplant is of a species selected from the group consisting of J. nigra, J.cinerea, and J. regia. In some embodiments, the plant is J. nigra. Insome embodiments, the material from which the extract is made isselected from the group consisting of nut hull, leaf, nut shell, root,bark, and wood.

In some embodiments, the extract is made from nut hull. In someembodiments, the extract is an acid extract. In some embodiments, theacid extract is an extract made using an organic acid. In someembodiments, the acid is selected from acetic acid and citric acid. Insome embodiments, the extract is an alcohol extract, and the compositionfurther comprises an organic acid or acid anhydride. In someembodiments, the alcohol used for the alcohol extraction is ethanol. Insome embodiments, the organic acid is a carboxylic acid. In someembodiments, the acid is selected from the group consisting of aceticacid and citric acid. In some embodiments, the composition furthercomprises a surfactant. In some embodiments, the composition furthercomprises an emulsifier. In some embodiments, the emulsifier is apotassium phosphate. In some embodiments, the potassium phosphate istetrapotassium pyrophosphate.

In some embodiments, the composition further comprises a plant systemicinducer. In some embodiments, the plant systemic inducer is selectedfrom the group consisting of salicylic acid, jasmonic acid, isonicotinicacid, dichloroisonicotinic acid, phosphorous acid, cinnamic acid,chitosan, humic acid, and a beta-1,3 glucan. In some embodiments, theplant systemic inducer is salicylic acid. In some embodiments, thecomposition comprises both an acid extract and an alcohol extract of thefirst juglone-producing plant. In some embodiments, the compositionfurther comprises an acid extract or alcohol extract of a secondjuglone-producing plant of the family Juglandaceae. In some embodiments,the first and said second juglone-producing plants are of the genusJuglans. In some embodiments, the first and second juglone-producingplants are selected from the group consisting of J. nigra, J. cinerea,and J. regia, provided that said first and said second juglone-producingplants are not of the same species. In some embodiments, the materialfrom which the extract from said second juglone-producing plant is madeis selected from the group consisting of nut hull, leaf, nut shell,root, bark, and wood. In some embodiments, the extract of the secondjuglone-producing plant is an alcohol extract and the alcohol isethanol. In some embodiments, the extract of said secondjuglone-producing plant is an alcohol extract and the compositionfurther comprises an organic acid or acid anhydride. In someembodiments, the composition comprises an acid extract of said firstjuglone-producing plant and an alcohol extract of said second jugloneproducing plant.

In a further group of embodiments, the invention provides methods ofinhibiting nematode damage to a first plant. The methods compriseapplying to soil contacting the roots of the plant an extract ofmaterial from a juglone-producing plant of the family Juglandaceae, saidextract selected from the group consisting of an acid extract and analcohol extract of said material, wherein contacting said soil with saidextract kills nematodes in said soil, thereby inhibiting nematode damageto said first plant. In some embodiments, the juglone-producing plant isa member of a genus selected from the group consisting of Carya,Engelhardtia, Juglans, Platycarya and Pterocarya. In some embodiments,the juglone-producing plant is a member of the genus Juglans. In someembodiments, the juglone-producing plant is of a species selected fromthe group consisting of J. nigra, J. cinerea, and J. regia. In someembodiments, the juglone-producing plant is J. nigra. In someembodiments, the material from which the extract is made is selectedfrom the group consisting of nut hull, leaf, nut shell, root, bark, andwood. In some embodiments, the extract is an alcohol extract and thealcohol is ethanol. In some embodiments, the extract is an alcoholextract and the composition further comprises an organic acid or acidanhydride. In some embodiments, the organic acid is a carboxylic acid.In some embodiments, the carboxylic acid is selected from the groupconsisting of acetic acid and citric acid. In some embodiments, theextract is an acid extract. In some embodiments, the acid extract ismade with a carboxylic acid. In some embodiments, the carboxylic acid isselected from the group consisting of acetic acid, peracetic acid, andcitric acid. In some embodiments, the extract further comprises asurfactant. In some embodiments, the extract further comprises anemulsifier. In some embodiments, the emulsifier is a potassiumphosphate. In some embodiments, the extract comprises both an acidextract of said material and an alcohol extract of said material. Insome embodiments, the method comprises contacting the soil with analcohol extract of a first juglone-producing plant and an acid extractof a second juglone-producing plant. In some embodiments, the extract isof at least two juglone-producing plants of the family Juglandaceae. Insome embodiments, the plant as to which nematode damage is to beinhibited and the juglone-producing plant used to produce the extractare of the same species.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a graph of the percent reduction in nematode infestation ofsoil after the soil was treated with the agent indicated, compared tountreated soil. Vertical axis: percent reduction of nematodes. Legend:bar with lines sloping downward from left to right: 1,3 dichloropropene;bar with horizontal lines, imidacloprid; bar with lines sloping upwardfrom left to right, an alcohol extract of the invention.

FIG. 2 is a graph of the percent reduction in nematode infestation ofplant roots after the soil in which the plants were being grown wastreated with the agent indicated, compared to plants grown in untreatedsoil. Vertical axis: percent reduction of nematodes. Legend: bar withlines sloping downward from left to right: 1,3 dichloropropene; bar withhorizontal lines, imidacloprid; bar with lines sloping upward from leftto right, an alcohol extract of the invention.

DETAILED DESCRIPTION OF THE INVENTION

Introduction

Surprisingly, it has now been discovered that extracts prepared bysteeping materials from juglone-producing member of the familyJuglandaceae, and particularly from trees of the genus Juglans in anacid solution, or, even more preferably, an alcohol solution, results incompositions with dramatic anti-nematode activity. The compositions areeffective in reducing nematode numbers on plants in the field and theirhigh activity permits sharply reducing the amount of the compositionthat needs to be applied in the field. Moreover, the high anti-nematodeactivity of the compositions means they can be applied as concentrationsthat do not inhibit the growth of juglone-sensitive plants. Thus, theinvention provides a new method of protecting plants from nematodeinfestations by reducing nematode infestations prior to planting(pre-plant) and after the soil has been planted (post-plant).

Studies underlying the present invention indicate that the compositionsof the invention are surprisingly more useful as a field agent againstnematodes than is pure juglone, which is apparently the only componentof walnut extracts previously identified as having anti-nematodeactivity. The poster by Wuyts et al. noted in the Background sectionreported that, under in vitro conditions, juglone was lethal to half apopulation of the nematode P. penetrans at concentrations of 90 partsper million (“ppm”) (the dose of an agent required to kill 50% of apopulation is known as its “LD₅₀”; thus, juglone had an LD₅₀ of 90 ppmon P. penetrans) after exposure for 72 hours.

It is known, however, that it is fairly easy to kill nematodes whilethey are bathed in water under in vitro conditions. Under suchconditions, the nematodes are in constant contact with whatever agent isin the water, and there are no interactions that might ordinarily occurbetween the agent and the multitude of organic and inorganic compoundspresent in normal soils. In field use, however, it is impracticable toflood a field with a solution of juglone for a period of days to keepnematodes in contact with the juglone. Moreover, juglone is not verysoluble in water and does not move far in soil, while for effectivecontrol of nematodes it is generally desirable to kill the nematodes inthe top 12 inches of soil. Thus, a solution of juglone and water may besuitable for use as a nematicide in hydroponic applications, but isgenerally not suitable for use as a nematicide on plants growing insoil.

In contrast, the compositions and methods of the invention have beenshown to be effective in the field, and can be used to penetrate thesoil to protect the bulk of the root mass. Moreover, the compositionscan be applied without the need to modify traditional farm watering andfertilizer application equipment. The compositions of the invention canbe applied at rates which render them commercially viable compared tothe chemically based nematicides that would otherwise be needed.Further, since the compositions of the invention are far less toxic tohandle and apply than conventional pesticides, use of the compositionsand methods of the invention reduces the exposure of farmers andagricultural workers to toxic chemicals they may be poorly trained orequipped to use. And, since the compositions are both relativelynon-toxic to produce and much less environmentally damaging to use thanconventional nematicides, the invention provides meaningful protectionfrom nematodes at sharply cost to the environment. Finally, as notedabove, the protection has been demonstrated with respect to a variety ofplants. Thus, the compositions and methods of the invention provide aneasy and cost effective substitute for toxic chemical nematicides.

The compositions of the invention are surprisingly more effective thanare extracts of similar plant materials using water. Assigning a waterextract of the plant materials a nematode-killing value of one forcomparison purposes, the studies underlying the present invention foundthat acid-based extracts of the plant materials were approximately 50%more effective in killing nematodes. Two alcohols were used: glacialacetic acid and a 30% solution of citric acid in water. Each was used toextract material from plant material, and each gave an extract withnematode-killing activity about 50% higher than extracting the plantmaterials with water.

Surprisingly, extractions of similar plant material with alcoholresulted in extracts which were some 80% more effective in killingnematodes than a water-only extract from the same material. Using anextract made by steeping the plant material with an alcohol, and thenadding an acid and surfactants to the extract, as discussed below,resulted in compositions with about 100% more activity than did awater-only extract of the same plant material. Thus, the inventionprovides new compositions that are surprisingly more effective atkilling nematodes than water-based extracts.

Interestingly, juglone-producing plants are themselves subject tonematode attack. It is expected that the compositions and methods of theinvention will be useful in inhibiting nematode attack onjuglone-producing plants as well as on plants that do not producejuglone.

Definitions

“Juglone” is a compound known chemically as5-hydroxy-1,4-naphthoquinone, or1,5-dihydroxy-4-naphthalenyl-β-glucopyranoside. It is availablecommercially from, for example, the Calbiochem division of EMDBiosciences, Inc. (San Diego, Calif.).

The term “crop,” as used herein usually refers to plants raised infields in an agricultural setting, and includes, along with carrots,tomatoes, grapes, oranges, and other plants intended for human or animalconsumption, plants intended for use as fibers, plants to be used as orprocessed into medicaments, plants grown for fragrance, flowers, herbs,and decorative, recreational, and ornamental plants. In this context,the term includes tree farms, such as those growing conifers to be usedas Christmas trees, and grasses grown for use as turf. The term can alsoencompass plants grown hydroponically, or preferably, in soil, ingreenhouses.

The terms “plant systemic inducer,” “systemic inducer of resistance,”and “systemic inducer” are used herein as synonyms and as used hereinrefer to chemical or biological agents that induce pathogen resistanceafter a plant is contacted with a plant systemic inducer. Examples ofchemical plant systemic inducers include, inter alia, salicylic acid,jasmonic acid, isonicotinic acid, dichloroisonicotinic acid, phosphorousacid, and cinnamic acid, chitosan, humic acid, and beta-1,3 glucans andother mixed glucans.

One skilled in the art will recognize that biological plant systemicinducers include, inter alia, bacteria, viruses, fungi, and nematodes.Kelp, a form of seaweed, and some other seaweeds, are rich sources ofbeta glucans and can be used as systemic inducers in the compositionsand methods of the invention. Unlike bacteria, viruses, and most othermicrobiological agents, kelp and other seaweeds are sold commercially asfertilizers and are available as liquid extracts or as dried powders. Inthis regard, they more resemble agricultural chemicals and for ease ofdiscussion, will therefore be treated as chemical inducers herein unlessotherwise indicated. Finally, humic acid, a component found in the humusportion of some soils, also acts as a systemic inducer. Thus, the term“systemic inducer” can, where appropriate, include reference to humicacid. In preferred embodiments, we have found good results by includinghumic acid along with other systemic inducers in the compositions andmethods of the invention. Accordingly, the addition of humic acid toother systemic inducers will generally be specifically denoted herein.

Contacting “soil in contact with the roots of a plant” with acomposition of the invention refers to soil in sufficiently closeproximity to the roots of plants intended to be treated that the amountof the composition applied can be reasonably expected to reach the rootsof the target plants. With respect to crops in a field or trees in agrove, for example, the phrase refers to soil surrounding the roots ofthe crops in that field or the trees in that grove.

As used herein, reference to an “acid extract” or to an “alcoholextract” of plant material refers to the liquid product resulting fromsteeping the plant material for a given period of time in an acidsolution (to create an acid extract) or in an alcohol solution (tocreate an alcohol extract). For convenience of reference, use of theterm “extract” herein refers to an acid extract or to an alcohol extractexcept where it is clear in context that the reference is to an extractmade by steeping a plant material solely in water.

The phrase “reactive oxygen species” (abbreviated herein as “ROS”)describes oxygenated compounds which serve as a source of oxygenatedradicals. The term is considered to be synonymous with “activated oxygenspecies.” These compounds include, inter alia, peracetic acid, sodiumperoxide, potassium oxide, potassium peroxide, calcium peroxide,magnesium peroxide, urea peroxide, hydrogen peroxide (H₂O₂),hydroperoxides (ROOH), peroxides (ROOR), and superoxides, where R is analkane, alkene or alkyne, branched or unbranched, and of between 1 and12 carbons and Ar is an aromatic ring, usually of 6 carbons, or acombination of such rings. As used herein, the term “reactive oxygenspecies” excludes the gas ozone.

Humus is the major organic component of soil. “Humic acid” is a phenoliccomplex which is a component of humus. Commercially, humic acid isgenerally extracted from what is described as a salt-free deposit ofhighly oxidized carbon known as “Leonardite.” Extraction of humic acidfrom Leonardite is described in detail in U.S. Pat. No. 5,607,856.

“Peracetic acid” is made by reacting glacial acetic acid with hydrogenperoxide. Since this reaction does not go to completion but insteadresults in a equilibrium being reached, at any point in time all threechemical species, peracetic acid, acetic acid, and hydrogen peroxide,will exist. A method for making peracetic acid suitable for use inconnection with the compositions of the present invention can be foundin Moon, U.S. Pat. No. 6,582,961, which is hereby incorporated byreference.

The phrase “field capacity” refers to the percent water remaining in thesoil two to three days after having been saturated and after freedrainage has practically ceased.

As used herein, “extracting” or “extraction” of a material meanscontacting the material, which if solid is preferably dried and crushedor ground, with an appropriate solvent to remove the substance orsubstances desired to be extracted from the material. Such an extractionmay be carried out by conventional means; for example, by using anextraction apparatus which retains the solid material in a holder andallows the solvent to flow through the material, or by blending thesolvent and material together and then separating the liquid and solidphases or two immiscible liquid phases, such as by filtration or bysettling and decanting.

Unless otherwise specified, references herein to “parts per million” (or“ppm”) used in reference to the compositions of the invention refers tothe concentration of the solution containing the plant material extract,including any chelating agents, surfactants, or other chemicals whichmight also be present in the mixture as will be made clearer in thediscussion below. Typically, the composition will be an aqueous solutioncomprising an alcohol.

As used herein, “an effective amount” of a composition of the inventionis an amount that, when applied to soil infested with nematodes or tothe roots of a plant infested with nematodes, results in a decrease ofat least 10% in the number of nematodes infesting the plant, morepreferably 20%, still more preferably 50% and most preferably 90% ormore.

Compositions of the Invention

1. Plant Materials for Extraction

In general, the starting material for the compositions of the inventioncan be any juglone-producing member of the family Juglandaceae, and arepreferably from trees of the genus Juglans. As noted above, juglone isnot believed to be responsible for the dramatic effect seen with thecompositions of the invention. It is believed, however, that thepresence of juglone is a useful marker for members of the Juglandaceaethat are useful for preparing the compositions of the invention.Accordingly, members of the family that produce juglone, includingCarya, Engelhardtia, Juglans, Platycarya and Pterocarya can be used.Within the family, members of the genus Juglans are preferred. Thespecies J. nigra (black or American walnut), J. regia (English walnut),and J. cinerea (butternut), are preferred, with the first two being morepreferred and J. nigra being the most preferred. Testing of hulls andleaves of J. nigra and J. regia have indicated that they haveapproximately the same effectiveness in killing nematodes. Materialsfrom one or more members of the Juglandaceae can be used together toform the compositions of the invention. For example, material from J.nigra, J. cinerea, and J. regia, or from any two of these, can be mixedtogether and used as the base for the alcohol extracts described below.

The studies underlying the present invention indicate that any part ofthe plants can be used. The highest amounts of activity have been notedusing the nut hulls and the leaves, with the hulls producing thestrongest nematicidal effect. Every other part of the tree tested thusfar, however, has also had activity and can be used, including the wood,bark, shells. Walnuts will generally not be used for preparing thecompositions of the invention simply because the nuts usually cost moreper pound than wood chips, nut hulls, bark, and other by products of nutor wood production. But, walnuts can be used to make the compositions ofthe invention if desired. If nuts are used in making the compositions,it is desirable that other portions of the plants also be included inthe materials to be extracted.

The invention provides an extra economic use for waste parts of thetrees used to form the compositions of the invention. For example, hulls(also known as husks) are a waste product of walnut production, whilesawdust and wood chips are waste products of producing walnut wood forfurniture and other uses. These waste materials can be used in producingthe compositions of the invention. Moreover, after being used to producethe compositions of the invention, the materials can be dried and thenused, for example, as biomass in power generation or, in the case ofwood chips and sawdust, as a base for forming manufactured wood productsand the like. Since these waste materials are produced in the course ofother uses, they are inexpensive and reduce the cost of preparing thecompositions, while providing an extra benefit to the grower orprocessor, who can obtain value for materials that may otherwise need tobe disposed of economically.

2. Use of Acids or Alcohol for Extraction

The compositions of the invention are extracts of the plant materialsdescribed above in an aqueous solution of an alcohol, in an acid, or inan aqueous solution of an acid (as noted in the Introduction, one of thealcohol extracts was made using glacial acetic acid, which is almostpure acetic acid. It is believed that a solution in which the aceticacid is diluted to between about 30-80% would result in even betterextraction of nematode-killing substances from the plant material.).

As noted in the Introduction, alcohol extraction results in compositionswith the highest nematode-killing activity. Methanol and isopropanol canbe used. Preferably, however, the alcohol is ethanol. While juglone isknown to be soluble in ethanol, a number of other napthoquinones arealso present in the plant materials that can be used in making thecompositions of the invention, and are also known to be soluble inethanol. Walnut hulls, for example, comprise not only juglone(5-hydroxy-1,4-naphthoquinone), but also 1,4-naphthoquinone,2-methyl-1,4-naphthoquinone, and plumbagin(5-hydroxy-2-methyl-1,4-naphthoquinone). The hulls also contain tanninsand iodine. A number of compounds of other types may also be present inthe compositions of the invention. For example, the leaves of J. regia(English walnut) are known to contain, in addition to juglone, ascorbicacid, carotene, quercetin, cyanadin, kaempferol, caffeic acid, andtraces of p-coumaric acid, hyperin (0.2%), quercitrin,kaempferol-3-arabinoside, and quercetin-3-arabinoside. Without wishingto be bound by theory, it is believed that it is one or more of theother constituents present, or a synergism due to the combination ofsome or all of the constituents, that is responsible for the dramaticanti-nematode activity seen with the compositions of the inventioncompared to juglone alone.

It is also noted that ethanol extracted compositions are surprisinglymore effective than water extractions, and that the naphthoquinones aresoluble in alcohol. Thus, it is surmised that it is the combination ofjuglone and other naphthoquinones that are particularly responsible forthe dramatic anti-nematode effects using the compositions of theinvention in the methods of the invention, although other components mayalso be involved. It should be noted that, while juglone is notconsidered to be responsible by itself for the nematicidal effects ofthe compositions of the invention, it is considered to be a marker forthe presence of other compounds, such as other napthoquinones, which bythemselves or together are responsible for these effects.

The solutions used to extract active ingredients from the startingmaterials described below comprise a solution of an acid or alcohol inwater. A combination of acid and alcohol can also be used if desired.

The acid or alcohol is preferably present at a concentration of between10% and 90%, more preferably between about 20% and 80% and morepreferably still between 40% and 75%. For alcohol extractions,particularly good results have been found using a concentration betweenabout 50% and about 70% by weight of alcohol; accordingly, alcoholsolutions in this range are the most preferred. While alcohols such asethanol can be obtained in a pure form (e.g., “absolute” ethanol), theyare typically commercially available as a high percentage solution inwater. Ethanol, for example, is typically available commercially as a95% solution of alcohol in water. In the studies underlying theinvention, a 70% solution of ethanol was used and is preferred for easeof handling. Absolute ethanol typically has a few parts per million ofbenzene left over from the purification process to remove water from the95% solution obtained from fractional distillation and is lesspreferred. In the U.S., ethanol is often denatured to ensure that it isnot used for drinking purposes without payment of the appropriateFederal taxes. If denatured ethanol is used, it should be denatured witha denaturant that is not toxic to plants at the concentration at whichit would be present when the extract is applied to the soil.

Acid extraction of the plant materials discussed in the precedingsection also results in compositions with nematode-killing activitysurprisingly higher than extracts made from the same material using onlywater. Conveniently, the acid is one that is not toxic to plants, andthat is environmentally friendly. Preferably, the acid is an organicacid. Preferred organic acids include acetic, citric, peracetic, andisocitric acids, with acetic acid being most preferred. Acetic acid andcitric acid, in particular, are widely available, inexpensive, and notharmful to plants at the concentrations the compositions are applied inthe field.

For convenience, the combination of the acid or alcohol solution andwater solution to form the medium into which the plant material isplaced for extraction will be referred to as the “extraction solution,”and the solution formed by the dissolution of solutes from the plantmaterial into the extraction solution will be called the “extract.” Theplant materials can soak in the extraction solution for as little as 10minutes. On the other hand, the potency improves with longerextractions. Longer steeping is, therefore, desirable, with 1 hour, 2hours, 3 hours, 4 hours, and 12 hours being progressively more preferredand 24 hours still more preferred. After about 48 hours, the potencydoes not appear to increase notably; if it is still increasing, the rateof increase of potency becomes very slow. On the other hand, longersoaking does not appear to be deleterious. It has not been noted thatthe extract can become too strong. Thus, the materials may be permittedto soak in the extraction solution for as long as desired; for example,the materials can be left to steep for as long as one or two months.Production of potent extracts can be maximized if the steeping time isnot much greater than necessary to produce maximum potency.

Under some circumstances, however, it may be convenient to steep thematerials for a longer period. For example, the producer may find itconvenient to place the plant materials in the extraction solution on aFriday and to leave them in the solution over the weekend, or for a weekor more over a vacation or the like. During periods of low demand (forexample, over the winter), any plant materials already steeping in anextraction solution can simply be left in the solution until there is aneed for the extract Periods of about 48 hours, however, give areasonable balance of providing extracts of the maximum potency in theshortest period of time and are generally preferred.

The subject invention includes a process for preparing an extract oftissues of the plants of interest, such as hulls, leaves, bark, wood,shells and the like, by extracting the tissues using an acid solution ora solution of a water-miscible alcohol, such as methanol, ethanol,n-propanol or iso-propanol or mixtures of such alcohols. Ethanol ispreferred.

At present, even though husks are a waste material, they are notparticularly easy to obtain. Thus, while larger amounts can be used, forthe studies underlying the invention, an attempt was made to see howsmall an amount of material could be used. Compositions were made with5, 4, 3, 2, and 1% of hulls by weight in the starting materials, and allgave good nematicidal activity. Without wishing to be bound by theory,it is surmised that the substances extracted from the plant materialsmay reach a maximum. Thus, even ¼% by weight, or more preferably ½% byweight is likely to be sufficient in making the compositions of theinvention. While these percentages are sufficient for leaves and hulls,which have the highest activities, wood, bark, and other portions of theplant are expected to have less activity, and should be used in largerquantity for extraction. The juglone content can be used as rough guideas to how much to be used. That is, if the wood of a particular plant isknown to contain one-fifth the juglone content of the hulls, and acomposition using X pounds of hulls is known to be sufficient foradequate nematicidal activity for a given use, it is expected that acomposition with the same nematicidal strength can be made from the woodusing five X pounds of the wood.

If the extract has been made using an alcohol-based extraction solution,it is preferable to add an organic acid to the resulting extract (itshould be noted that in this case, the acid is not being added toextract substances from the plant material, but as an additive to theresulting solution. Thus, the acid can be added to the extract after theplant material has been removed. If desired, however, an acid can beadded to an alcohol solution so that the plant material is subjected toextraction by both the alcohol and by the acid.) Preferably the organicacid is a carboxylic acid. Preferred organic acids include acetic,citric, and isocitric acids, with acetic acid being most preferred. Acidanhydrides hydrolyse in the presence of water to yield the acid, andtherefore can be used in place of or with the acid in the compositionsof the invention. For example, acetic anhydride can be used in place ofacetic acid. Peracetic acid is in dynamic chemical equilibrium withacetic acid and can be used in place of or with acetic acid in thecompositions and methods of the invention. If used, the peracetic acidis preferably made by the process described in Moon, U.S. Pat. No.6,582,961. Acetic acid is commonly available and has the benefit offamiliarity to farmers and other growers, and is preferred.

The studies underlying the present invention have shown that thepresence of acetic acid in the solution reduces the period of timeduring which nematodes need to be exposed to the solution before theyare killed. Therefore, the solutions of the invention preferably includeacetic acid. Preferably, the acetic acid is added after the extractionof the plant material in the alcohol solution has occurred. If used, theacetic acid should be present in the range of from 1% to 50%, with about2% to about 25% being more preferred, 5% to about 20% being even morepreferred, 7.5 to about 15% still more preferred, and 10% being the mostpreferred. It is noted that acetic acid by itself will typicallypenetrate only into the top 2 inches of soil due to interactions withthe soil. Acetic acid by itself can kill nematodes by lowering pH. It isnot believed the activity of the compositions and methods of theinvention can be explained by the acetic acid content, however, sincethe amount of acetic acid used would not be expected to alter the pHbelow the top 2 inches of soil. Additionally, the amount of acetic acidrequired to lower the pH of 4 million pounds of soil (the weight of anacre-foot of soil) would be enormous, while studies underlying theinvention have provided a 90% reduction of nematodes over an acre-footof soil using only 15 gallons of the compositions of the invention.Clearly, much larger quantities of acetic acid would be needed to lowerthe pH of that much soil by any significant amount. Thus, the effectseen in adding an organic acid to the plant material extracts does notbe explained as a function of reducing the pH.

Optionally, small amounts (1-10%) of surfactants may also be added tohelp the solution filter through the soil and contact the plant roots.Surfactants are commonly used as wetting agents to improve thepenetration of agricultural chemicals. A number of surfactants, such asDow Corning® Q2-5211 Superwetting Agent (Dow Corning, Midland, Mich.),T-MULZ® phosphate esters (Harcros Organics, Inc., Kansas City, Kans.),and the DOWFAX™ series of nonionic surfactants (Dow Chemical Co.,Midland, Mich.), are suitable for use in agricultural applications andare commercially available. Preferred surfactants for use in thecompositions of the invention include Triton H-66™ and Tergitol™ 15 S.In a preferred embodiment, 2.5% of each of these two surfactants isadded to the solution. Other surfactants that are compatible for usewith plants can also be used. Compatibility can easily be tested byadding a solution of the surfactant at the contemplated concentration toa test plant or plot of plants and comparing the growth and health ofthe test plants against a control plant or plot of plants to which thesurfactant is not administered. The surfactants should be also becompatible with acetic acid, peracetic acid, or such other acid as maybe used in the solution. Compatibility can be tested in the same manneras that just described for determining the suitability of thesurfactant.

Preferably, the composition contains an emulsifier. A number ofemulsifiers and anti-foam agents suitable for agricultural use, such asT-MULZ® emulsifiers (Harcros Organics) and anionic and nonionicemulsifiers from Huntsman Surface Sciences (Houston, Tex.), are known inthe art and are commercially available. In a preferred form, theemulsifier is a potassium phosphate, such as potassium phosphatemonobasic, dibasic, or tribasic (tripotassium phosphate), which not onlyhelps emulsify the solution and aid in its dispersal in the soil, butalso acts as a chelating agent with metals in the soil. Tetrapotassiumpyrophosphate is a preferred potassium phosphate for use in thecompositions of the invention. The phosphate may be present in 1-20% byweight, more preferably 5-15%, and most preferably 10% of the overallsolution. For example, if the composition is to weigh 100 pounds, 10pounds may be of the potassium phosphate.

If an emulsifier that is not also a chelating agent is used, than it ispreferable that a chelating or sequestering agent suitable foragricultural use, such as Agri-Sequest-All (Sper Chemical Co.,Clearwater, Fla.) is also present. Citric acid is a preferred chelatingagent and 1 to 5% of citric acid is preferably included in thecompositions of the invention even if the emulsifier is also a chelatingagent, and especially if no emulsifier is used.

The nematicidal substances may be extracted from the plant tissue usingan extraction apparatus, where the alcohol solution is refluxed throughthe tissues, the plant material may be simply introduced into a solutionin a container, or the plant material may be placed in a container andthe solution poured over the material or otherwise introduced into thecontainer so that it comes into contact with the plant material, whichis preferably submerged. For example, hulls, leaves, branches and thelike can simply be placed in the extraction solution and allowed tosteep. Preferably, however, the surface area of the material isincreased prior to or while in contact with the extraction solution. Itwill be appreciated the larger the surface area of the material incontact with the solution, the more opportunity there will be forcomponents of the material to dissolve into the extraction solution, andthe shorter the time that will be needed for that dissolution to occur.It will further be appreciated that the total surface area of a branch,hull, shell, piece of bark or other part of the plant will increase asit is crushed, ground, cut, sliced or shredded. Some materials willalready be in a form that provides a suitably large surface area forcontacting the solution without the need for further processing. Forexample, sawdust and wood chips from timber, sawmill, and manufacturingoperations can simply be gathered up and placed in the alcohol solutionsto form the compositions of the invention. The alcohol is preferably notevaporated from the resulting liquid extract, as it is believed to helpmove the extract through the soil to the roots when the extract isapplied to plants.

Good results have been obtained preparing the compositions at roomtemperature. Room temperature preparation is generally preferable, sinceit avoids the cost of heating or cooling the materials. Highertemperatures may, however, permit extraction of even higher amounts ofnematicidal substances from the plant material. If it is desired toprepare the compositions at a temperature well below or above roomtemperature (for example, at 40° F. or at 140° F.), a small batch can bemade and tested for the composition

3. Combination with Systemic Inducers

Moon, U.S. Pat. No. 6,582,961, discloses that the resistance of plantsto a variety of pathogens can be increased by contacting the plants witha combination of reactive oxygen species and a plant systemic inducer.Surprisingly, studies undertaken in the course of the present inventionindicate that adding a plant systemic inducer to the acid or alcoholextracts described above further suppresses nematode infestations.Without wishing to be bound by theory, it is surmised that the acid oralcohol extracts tend to kill nematodes present in the soil, therebydiminishing the number available to attack the plants, while the plantsystemic inducer induces pathogen resistance in the plants which renderthem less susceptible to infestation. The effects of the two agentstherefore appears to be synergistic in decreasing nematode infestation,thereby inhibiting nematode damage of plants.

Preferred systemic inducers include salicylic acid, jasmonic acid,isonicotinic acid, dichloroisonicotinic acid, phosphorous acid, andcinnamic acid, chitosan, humic acid, and beta-1,3 glucans and othermixed glucans. Salicylic acid is particularly preferred.

Methods of the Invention

Typically, the life cycle for nematodes starts with an egg, followed byfour larval or juvenile stages (usually referred to as the L1, L2, L3and L4 stages), and an adult stage, with a molt between each stage. Thelife cycle for many nematodes is 28-30 days. Thus, the compositions ofthe invention are typically applied twice, once to kill the adultnematodes and once approximately 30 days later to kill any nematodesthat have hatched in the intervening time. If infestation recurs, thirdor even fourth applications can be made, but are usually not necessary.It is noted that some plant parasitic nematodes have life cycles asshort as two weeks, while some dagger nematodes may require a full year,and that the duration of the life cycle can vary depending on soil andthe prevailing temperature. For example, the northern root-knot nematode(Meloidogyne hapla) can vary from 17 to 57 days. Commercial growers aretypically aware of the particular nematode species that are the mostnumerous in their fields, area, or state; the length of time betweenapplications can be shortened (for species that reproduce more quickly)or increased (for species with longer reproductive cycles) asappropriate to control the nematode populations. Needless to say,growers facing a mixed population of nematodes with short and long lifecycles will tend to apply the compositions on a schedule designed toreduce the damage from the nematodes with the shortest life cycle of thepopulation.

It will be appreciated that some crops are only vulnerable to nematodedamage during an early part of their growth, and thus will not need afurther application if they are protected during the vulnerable period.For example, carrots are very vulnerable to nematode damage during theirfirst two weeks of growth, and thereafter are not strongly affected bynematode infestation. Thus, an application of the compositions of theinvention to the field prior to planting or immediately post-planting ofthe carrots will eliminate most or all of nematode damage to the crop.Typically, the compositions are applied at about 5000 ppm with the “germwater” and again 10 days later. By the time nematodes from surroundingareas can infiltrate the soil or a substantial number of eggs in thesoil hatch to provide a new infestation of nematodes, the carrot rootsare beyond the point at which the nematodes can affect the crop. Forother crops, the compositions are typically applied when there is a rootflush, that is, that the roots are first fleshing out from the seedling.

The compositions of the invention are applied at a rate of 1000 to about30,000 ppm, and more preferably about 1500 to about 20,000 ppm. In someembodiments, the compositions are applied at about 2000 ppm to about15,000 ppm, and more preferably about 3000 to about 10,000 ppm. In otherembodiments, the compositions are applied at about 3,500 ppm to about8,000 ppm, and more preferably about 4,000 to about 7,000 ppm. In yetother embodiments, the compositions are applied at about 4500 ppm toabout 6,000 ppm, and more preferably about 3000 to about 10,000 ppm.Most preferably, the compositions are applied at about 5,000 ppm. Asused herein, the term “about” recognizes that it is difficult to obtaina precise application and that the concentration of the composition willlikely vary within about 200 ppm in any given application. It is alsounderstood that such small variations will not have any measurableeffect on the nematicidal efficacy of the application.

The studies underlying the invention indicate that a concentration ofabout 5000 ppm kills 90% of nematodes. Since farmers have beenaccustomed for years to mixing pesticides, fertilizers, and otheragricultural chemicals for use in their fields, the application of thecompositions of the invention are well within a farmer's skill.Nonetheless, errors do happen. The preferred concentration of 5000 ppmis such that if the farmer accidentally halves the concentration, itwill still be high enough to provide significant effect, while if it isaccidentally doubled, it will not be toxic to the plants. Lower orhigher concentrations can, of course, be employed, at the user's option,but are preferably within the limits noted above. Phytotoxicity has notbeen noted at concentrations as high as 20,000 ppm.

Application of the Compositions of the Invention

The compositions of the invention are typically applied to the soil sothat they can kill nematodes in and around plant roots. The soil ispreferably first saturated to wet the particles of the soil so that thecompositions can move freely in the soil and reach the roots of theplants. Therefore, preferably the soil is saturated to field capacitywith ordinary water prior to application of the compositions. Thecompositions are then applied at a concentration of between 1000 andabout 30,000 ppm, as noted above.

It will be recognized that the intention is to have an effectiveconcentration of the compositions at the depth in the soil the roots ofthe plant are to be found. Desirably, the compositions are applied toprovide a concentration of about 5000 ppm at and around the roots. Formost plants, early in their life, the roots will be close to the surfaceand the concentration at the roots will be close to that applied to thesurface. Young plants and plants of some species, such as the grassesused on golf courses, lawns and parks, tend to have short, fibrousroots. For these plants, applications of 5000 ppm to the soil surfacewill provide approximately that concentration to the roots and to thesoil around the roots, to kill root lesion and root knot nematodes,among others.

While some grasses and younger plants have shallow root structures, manyplants and many more mature plants have deeper root structures, often 4to 12 inches into the soil. The rule of thumb in the art for preventingnematode damage is that the majority of roots involved in nutrient andwater uptake occur in the top 12 inches of soil, while deeper roots tendto be involved in anchoring the plants. In sandy, aerated soils, theroots involved in nutrient transport can extend down to 18 inches.Penetration of the compositions of the invention into the first foot ofthe soil, however, will provide protection to the feeder roots, which donot develop protective coverings, and is anticipated to be beneficial inenhancing the survival and health of the plants.

The compositions of the invention can be applied in several ways. Asfarmers and other practitioners will be aware, 3000 gallons of waterwill typically soak 1 acre to a depth of 12 inches (an “acre-foot”). Toprovide 5000 ppm of the compositions of the invention, 15 gallons of thecompositions is added to the water supply and applied to the field. At 9pounds per gallon, this amounts to 135 pounds of the composition.Alternatively, 30,000 ppm of the composition can be applied to thesurface of the soil, with a water “push” of applying water to the soilto move the composition into the acre-foot of soil to provide aconcentration of 5000 ppm down to 12 inches. Such “water pushes” tocreate concentration gradients are commonly used by farmers in applyingagricultural chemicals and are well known in the art.

It will be appreciated that for a golf course, which has grasses withroots penetrating only to perhaps the first 5-6 inches of soil, only1000 to 1500 gallons of water will be needed, and only 6-7½ gallons ofthe compositions are needed to provide 5000 ppm of the composition inthe water.

It should be noted that the farmer is usually well aware of the flowrate per acre of the irrigation or other soil application system inplace on his or her property, as well as the acreage to be covered. Thefarmer can calculate the amount of water which will be used in wateringthe land for any particular amount of time (for example, 300 gallons perminute times 50 acres times 30 minutes is 450,000 gallons of water). Thefarmer can then calculate how much is needed to result in an applicationof the desired concentration of the solution.

What is desired is that the solutions result in the presence of thepreferred concentration of the plant extract for between 10 and 100hours, more preferably for between 12 and 72 hours, and more preferablystill for between 20 to 50 hours. If the composition is of an alcoholextract that includes an organic acid, such as acetic acid, peraceticacid, or citric acid, the time for the presence of the plant extract canbe at the shorter end of the time range, while compositions without anorganic acid should be applied for the longer end of the range. Thus, ifacetic acid is used in the solution, the plants should be in contactwith the recommended concentration of the plant extract for 20-28 hours,with 24 hours being preferred for convenience, whereas if acetic acid oranother acid is not present, the plants should be in contact with therecommended concentration of the plant extract for 40-50 hours, with 48hours being preferred for convenience.

The periods mentioned above for contacting plant roots with thecompositions of the invention are intended to describe periods effectiveto cause a reduction in nematode number sufficient to cause a noticeabledifference in the health of the plant. The soil around the plants shouldnot be treated in a manner that would reduce the concentration of thecompositions during the periods stated. For example, once the desiredconcentration is achieved, it is desirable that the soil not be wateredagain for the period in question so that the effective concentration isnot reduced. Similarly, it is undesirable to apply the compositions ofthe invention when a substantial rain is expected within the period inwhich it is desired that the compositions be present. On the other hand,the compositions of the invention are not deleterious to the plants andcan be left in place after the desired period has elapsed.

The compositions are typically applied to the soil by being run througha hose, pipe, drip, sprinkler, irrigation channel, or other mechanism.In practice, agriculture is not a science and the devices used aretypically not precision equipment. Accordingly, when the water flow isturned off, water will typically continue to drip or run from the hoseor through the irrigation channel or other applicator for some time. Itis therefore understood that the times of application will generally bean approximation and will be measured from the start of the flow of themixture to when the flow of the mixture is turned off, whether or notsome of the mixture continues to drip or run from the applicator.

Persons of skill are aware that non-chemical methods, such as croprotation and cover crops, are used instead of or in conjunction withchemical methods to control nematodes. The compositions of the inventioncan be used in conjunction or in place of with these methods.

Uses of the Invention

The invention can be used to protect almost any plant susceptible tonematode damage. Although some plants are considered to be susceptibleto juglone, the concentration of juglone when the compositions of theinvention are applied at the concentration contemplated herein that evensusceptible plants will not be damaged. The plants to be protected bymeans of the invention can be dicots, such as carrots, lettuce,tomatoes, grapes, citrus fruits, and beans, or monocots, such as corn.The plants can be grown for human or animal consumption, such as grains,vegetables, and fruits, can be intended for decorative use, such asflowers, or can be intended for ornamental use, such as trees grown foruse as Christmas trees or plants intended for use as house plants.Further, they can be plants grown for fiber, such as cotton plants, orfor use as turf. The compositions are especially useful, for example, ongolf courses, lawns and ballfields. Most commonly, the invention will beused to protect plants grown in fields as crops or in other openconditions, such as tree farms or turf; the invention can, however, alsobe used to protect plants grown in settings such as greenhouses andhothouses should nematode infestations be found in the soil in suchenvironments. The compositions can also be used in hydroponicapplications; this use is, however, less preferred.

It is anticipated that the compositions of the invention will be useful,for example, in preventing or reducing infestation of young citrus treesfrom the burrowing nematode, Radopholus citrophilus, causal agent of‘spreading decline of citrus’; the citrus nematode, Tylenchulussemipenetrans, causal agent of ‘slow decline of citrus’; two species oflesion nematode, Pratylenchus coffeae and P. brachyurus, causal agentsof ‘citrus slump’; and the sting nematode, Belonolaimus longicaudatus,and will reduce the infestation of mature trees by these nematodes.

Because the invention protects crops against at least a portion of thedamage which would otherwise be caused by nematodes, a higher percentageof the crops grown for human consumption can be sold as first qualitycrops. Moreover, since less of the crop is unmarketable, the inventionresults in a higher yield per acre. These factors combine to result inhigher revenues per acre for the farmer, and also reduce the level ofinfestation necessary before it is economically advantageous to use theinventive compositions and methods.

EXAMPLES Example 1

This Example describes an exemplar composition of the invention.

To make an exemplar 100 pounds of a 1% solution of a juglone-producingplant of the family Juglandaceae, the following is mixed:

Mix 1:

-   41 pounds deionized water, and-   10 pounds tetrapotassium pyrophosphate,-   for a total of 51 pounds of Mix 1.    Mix 2:-   14 pounds of 70% ethanol,-   10 pounds of 99% acetic acid, and-   1 pound of walnut hulls,-   for a total of 25 pounds.    Mix 3:-   22 pounds of deionized water, and-   2 pounds of citric acid,-   for a total of 24 pounds.

The three mixes were mixed together, for a total of 100 pounds ofproduct.

The walnut hulls can be left in the solution or, preferably, filtered orstrained out of the liquid before application to plants or the field.

In the Example above, the three mixes were prepared separately forconvenience of dissolving the different solutes. Since Mix 2 shouldsteep for 24-48 hours, it can be made before the other two. Forconvenience, however, all three mixes are made at the same time. Oncemix 2 has steeped for the desired period of time, it can be mixed intothe other two, or the three mixes can be transported to the site of use,mixed and applied. Deionized water was used in some of the studiesunderlying the invention to reduce artifacts that might be introducedfrom minerals in the water; in field use, however, regular irrigation orpond water or the like would be used to reduce cost and complexity.

The amounts set forth above can be scaled up to provide largerquantities or down to provide smaller quantities. Quantities as small as100 grams and as large as 2000 pounds have been made by simply scalingup or down, as appropriate, the amounts set forth above.

Example 2

A field trial was conducted on an orange grove, comparing the effect ofthe composition described in Example 1 (under its trade name,NatureCur™) against two widely used, commercially available nematicides,an emusifiable concentrate of 1,3 dichloropropene which can be appliedto the soil after plants are planted (called a “post-plant” application)(Dow AgroSciences LLC, Indianapolis, Ind.), shown on the accompanyingcharts as “Cordon,” and imidacloprid, an insecticide marketed under thename Admire® (Bayer CropScience LP, Research Triangle Park, N.C.). Forthe soil treated with Cordon and the soil treated with Admire®, singleapplications of the agents were made in mid-May. The product NatureCur™was applied in once in mid-May, once 30 days later in mid-June, and onceagain 30 days later in mid July, each time at a concentration of 5000ppm. The soil in the grove was a clay loam, a very dense, heavy soil inwhich it is difficult to get agents to travel. Thus, the soil in thisgrove provided a particularly difficult test condition for NatureCur™,which has to infiltrate through the soil in water.

Samples were taken of the soil around the plants and of the roots. Thepercentage of reduction in number of nematodes in soil treated with thethree agents compared to untreated soil is shown in Table 1 and FIG. 1.

TABLE 1 Percent reduction in Agent: nematodes in soil: 1,3dichloropropene 58% Imidacloprid 32% NatureCur ™ (Walnut Extract) 55%

The percentage of reduction in number of nematodes in roots of plantswhose soil was treated with the three agents compared to roots of plantsin untreated soil is shown in Table 2 and FIG. 2.

TABLE 2 Percent reduction in Agent: nematodes in roots: 1,3dichloropropene 61% Imidacloprid 46% NatureCur ™ (Walnut Extract) 30%

A comparison of the two Tables shows that the walnut extractsignificantly reduced nematode populations in both the soil and in plantroots. The fact that the walnut hull extract showed a greater percentageof reduction of nematodes in the soil than in the roots indicated thatthe nematodes had successfully infested the plant roots prior to theapplication of the product in mid-May, indicating that application ofthe product earlier in the growing season would result in even greaterreductions in nematode infestation of the plants. It was also noted thatAdmire® is a systemic agent which is taken into the plant, and that thehigher kill numbers in the roots reflect the fact that the agent canenter the plant to kill nematodes already in the roots. It is expectedthat application of the walnut extract at the beginning of the growingseason, before the nematodes have had a chance to reach the roots, wouldreduce the nematode infestation by percentages closer to that observedin the soil.

Example 3

A field trial was conducted on a carrot farm to compare the effect onnematode levels of the composition described in Example 1 (under itstrade name, NatureCur™) against two widely used, commercially availablenematicides, Telone® II, a soil fumigant form of 1,3 dichloropropene(Dow AgroSciences LLC, Indianapolis, Ind.), and Vapam® (anhydrous sodiumN-methyldithiocarbamate, Amvac Chemical Corp., Los Angeles Calif.).According to the manufacturer, when Vapam® contacts soil, it convertsinto methyl isothiocyanate, a volatile, highly toxic fumigant.

In carrots, nematodes which attack the tip of the plant during the first20 days post emergence cause the carrot to “fork”. Forked carrots areunmarketable, and nematodes are the primary cause of forking. Thus,determining the percentage of carrots that are forked serves as ameasure of how much the compositions tested can reduce the economic lossor damage caused by nematodes to a carrot population.

The test area was divided into plots, each of which was a little lessthan an acre in size. Each agent was tested on ten replicate plots.Following application of the agent, a like-size strip of carrots washarvested from each plot and examined for forking.

Agent Plot Forking/No. of Carrots NatureCur ™ West 1 2 of 19 NatureCur ™West 2 1 of 19 NatureCur ™ West 3 3 of 19 NatureCur ™ West 4 2 of 14NatureCur ™ West 5 1 of 19 NatureCur ™ East 1 0 of 8  NatureCur ™ East 20 of 10 NatureCur ™ East 3 0 of 11 NatureCur ™ East 4 0 of 10NatureCur ™ East 5 0 of 6  Total: 9 of 135, or 6.67%

Vapam ® West 1 1 of 12 Vapam ® West 2 [Not used] Vapam ® West 3 3 of 12Vapam ® West 4 1 of 10 Vapam ® West 5 2 of 13 Vapam ® West 6 0 of 6 Vapam ® East 1 0 of 7  Vapam ® East 2 1 of 12 Vapam ® East 3 1 of 17Vapam ® East 4 3 of 10 Vapam ® East 1 0 of 8  Total: 12 of 107, or11.21% *

Telone ® II West 1 1 of 11 Telone ® II West 2 1 of 10 Telone ® II West 30 of 10 Telone ® II West 4 2 of 12 Telone ® II West 5 0 of 18 Telone ®II East 1 2 of 20 Telone ® II East 2 1 of 8  Telone ® II East 3 1 of 10Telone ® II East 4 0 of 6  Telone ® II East 5 2 of 11 Total: 10 of 116,or 8.62% */ The carrots exposed to Telone ® II were older than thecarrots exposed to the other two agents when they were reviewed forforking. Since forking is considered due to nematode attack of thecarrot tip during the first 20 days of growth, however, examination ofthe forking in older carrots still permits comparison of nematodeinfestation levels of the carrots during the first 20 days in soilscontacted with the different agents.

The results of the study indicate that use of the walnut extract wasable to reduce forking by as much as half compared to carrots exposed tocurrent, widely used nematicides.

All publications and patent applications cited in this specification areherein incorporated by reference as if each individual publication orpatent application were specifically and individually indicated to beincorporated by reference.

Although the foregoing invention has been described in some detail byway of illustration and example for purposes of clarity ofunderstanding, it will be readily apparent to those of ordinary skill inthe art in light of the teachings of this invention that certain changesand modifications may be made thereto without departing from the spiritor scope of the appended claims.

1. A composition comprising an extract of a first juglone-producingplant of the family Juglandaceae and a plant systemic inducer whereinthe extract is produced by placing the plant into an extraction solutionwhere the extraction solution is an aqueous acid-alcohol solution having40% to 75% alcohol and the extract comprises the extract solution intowhich the plant is placed.
 2. A composition of claim 1 wherein saidfirst juglone-producing plant is a member of a genus selected from thegroup consisting of Carya, Engelhardtia, Juglans, Platycarya andPterocarya.
 3. A composition of claim 2, wherein said firstjuglone-producing plant is a member of the genus Juglans.
 4. Acomposition of claim 3, wherein said first juglone-producing plant is ofa species selected from the group consisting of J. nigra, J. cinerea,and J. regia.
 5. A composition of claim 4, wherein said firstjuglone-producing plant is J. nigra.
 6. A composition of claim 1,wherein the material from which the extract is made is selected from thegroup consisting of nut hull, leaf, nut shell, root, bark, and wood. 7.A composition of claim 1, wherein said extract is made from nut hull. 8.A composition of claim 1, wherein said acid is an organic acid.
 9. Acomposition of claim 8, wherein said acid is selected from a groupconsisting of acetic acid and citric acid.
 10. A composition of claim 1,wherein the alcohol is ethanol.
 11. A composition of claim 8, whereinthe organic acid is a carboxylic acid.
 12. A composition of claim 1,further comprising a surfactant.
 13. A composition of claim 1, furthercomprising an emulsifier.
 14. A composition of claim 13, wherein theemulsifier is a potassium phosphate.
 15. A composition of claim 14,wherein the potassium phosphate is tetrapotassium pyrophosphate.
 16. Acomposition of claim 1, wherein the plant systemic inducer is selectedfrom the group consisting of salicylic acid, jasmonic acid, isonicotinicacid, dichloroisonicotinic acid, phosphorous acid, cinnamic acid,chitosan, humic acid, and a beta-1,3glucan.
 17. A composition of claim16, wherein said plant systemic inducer is salicylic acid.
 18. Acomposition of claim 16, further comprising an aqueous acid-alcoholextract of a second juglone-producing plant of the family Juglandaceae.19. A composition of claim 18, wherein said first and said secondjuglone-producing plants are of the genus Juglans.
 20. A composition ofclaim 18, wherein said first and second juglone-producing plants areselected from the group consisting of J. nigra, J. cinerea, and J.regia.
 21. A composition of claim 18, wherein the material from whichthe extract from said second juglone-producing plant is made is selectedfrom the group consisting of nut hull, leaf, nut shell, root, bark, andwood.
 22. A nematicidal composition comprising an extract of a firstjuglone-producing plant of the family Juglandaceae and a plant systemicinducer wherein the extract is produced by placing the plant into anextraction solution where the extraction solution is an aqueousacid-alcohol solution having 40% to 75% alcohol and the extractcomprises the extract solution into which the plant is placed.